Running dotTrace 3.1 on multi-core machine

I’ve spent around 2 hours to figure it out, so at least I’ll write it down.
I’m using dotTrace 3.1 to do some analysis for .net web application running on Windows Server 2008 R2 (IIS 7.5).

I got strange numbers and was missing some data (methods calls) running “profile web application” until I set the affinity of the w3wp.exe process to single Node (single core). This can be done easily by opening the Tasks Manager, right click on w3wp process –> Set Affinity –> pick just one core.

Only then you should record the required page(s) and take the snapshot.